Continuous process for making a non-Newtonian paste or cream like material

ABSTRACT

A continuous process for preparing a paste or cream like material which comprises the steps of means for forming under non vacuum conditions at a temperature of 90° F. to 120° F. a first low viscosity homogenous slurry of at least one non aqueous solvent and a gelling or bodying agent; means for forming a second low viscosity homogenous slurry under non vacuum conditions at a temperature of 90° F. to 130° F., means for forming a low viscosity mixture of said first low viscosity slurry and said second low viscosity slurry by a high shear mixing under non vacuum conditions at a temperature of 90° F. to 130° F. for 0.1 to 5 seconds; means for transforming under non vacuum and non mixing conditions at a temperature of 65° F. to 120° F., said low viscosity mixture into a non Newtonian mixture; and means for deaerating said non Newtonian mixture under vacuum conditions for a period of less than 3 seconds to form said paste or cream like material.

BACKGROUND OF THE INVENTION

The present invention relates to a continuous process for themanufacture of a non Newtonian paste or cream like material such asdentrice or a cosmetic.

Dentifrices such as toothpaste or dental creams are generally extrudiblepastes which contain insoluble abrasives and/or polishing agents thatare used in the removal of plaque, stains and other deposits from theteeth and also help in polishing the teeth.

In one well known method of manufacture of dentifrices the dentifricesduring the manufacturing are subjected to high temperature and prolongedperiods of vacuum. These conditions cause a loss of volatiles such asflavoring agents during the manufacturing process. The improvedcontinuous process of the instant invention does not employ hightemperatures and prolong periods of vacuum thereby minimizing the lossof volatiles as well as reducing the cost of manufacturing due to lowenergy input requirements. Additionally, the resultant compositions ofthe instant invention exhibit non-Newtonian flow characteristics haveenhanced flavor, a G' value over a strain range of 0.1 to 0.5 percent at6.3 radians/second of at least about 4,000 dynes/sq. cm. and a complexviscosity over a strain range of 0.1 to 5% at 6.3 radians/second of atleast about 700 pascal--seconds thereby exhibiting improved rheologicalproperties and improved product stability.

Toothpastes can be made up by various and many well known techniques.One such technique is disclosed in U.S. Pat. No. 3,840,657 issued Oct.8, 1974, wherein a toothpaste composition is manufactured by making amixture of a liquid vehicle, gelling agent and polishing agent;degassing this mixture; preparing a second mixture of a syntheticorganic detergent and a liquid vehicle therefore, and degassing thismixture by raising it to an elevated temperature; and finally admixingthe first and second mixtures. In the manufacture of toothpastes,invariably the powdered constituents must be mixed and dispersed withthe other liquid ingredients contained in the final toothpaste product.Care must be taken to remove the air in the mixing in of the powders soas to prevent the entrainment of air in the resulting paste.

Various known methods are disclosed in such standard references as"Cosmetics: Science and Technology", by Sagarin, Volume I, pages510-511, published by Interscience Publishers, Inc. (1972). One suchmethod is the mixing of a paste mass under vacuum to remove theentrained air. The speed of removal will generally depend on the airquantity and mixer construction. Air can also be removed by atmosphericmixing followed by the use of a continuous deaerator such as a Versatoravailable from Cornell Machine Co. The efficiency of deaeration willagain be a function of the quantity of air present in the paste mass.

U.S. Pat. No. 2,751,328 teaches a continuous or semi continuous processfor the manufacture of toothpaste. The process of this patent teaches amethod similar to the instant invention but differs in the means offorming the dental paste and cream in it requires the maintaining of theslurry of the components at a temperature in excess of 140° F. up to270° F. for a residence time of 3-5 minutes with agitation. Theseconditions of the process of U.S. Pat. No. 2,751,328 because of theelevated temperature, residence time and agitation provide compositionswhich do not have improved G' values, increased complex viscosities,product stability, enhanced flavor or dispersion of the particles in thecomposition that are comparable to the compositions of the instantinvention because of the incomplete formation of the polymeric matrix.

U.S. Pat. No. 4,599,363 describes a continuous process for themanufacture of dentifrices. Like the previously described batchprocesses and unlike the continuous process of the instant inventionthis patent describes a process that employees high temperature andprolong periods of vacuum.

Accordingly, the instant improved continuous process for the manufactureof dentifrices produces dentifrices having non-Newtonian flowcharacteristics, enhanced flavor, and having improved rheologicalproperties of a G' value over a strain range of 0.1 to 0.5 percent at6.3 radians/second of at least about 4000 dynes/sq. cm, more preferablyat least about 5,000 dynes/sq.cm and most preferably at least about5,500 dynes/sq. cm and a complex viscosity over a strain range of 0.1 to0.5% at 6.3 radians/second of at least about 700 Pascal-seconds, morepreferably at least 800 Pascal-seconds and most preferably at leastabout 900 Pascal-seconds.

SUMMARY OF THE INVENTION

The present invention relates to a continuous process for themanufacture of a non-Newtonian paste or cream high viscosity likematerial such as dentifrice or a cosmetic which comprises the steps of:means for forming under non vacuum conditions at a temperature of about90° F. to 130° F., more preferably about 100° F. to 120° F. a firsthomogenous slurry of low viscosity of at least one non aqueous solventwhich is miscible with water and a gelling agent; means for forming asecond homogenous slurry of low viscosity under non vacuum conditions ata temperature of about 90° F. to 130° F., more preferably about 100° F.to 120° F. wherein the second homogenous slurry includes water and atleast one additive ingredient; means for forming a Newtonian mixture ofthe first slurry and the second slurry by high shear mixing under nonvacuum conditions at a temperature of about 90° F. to 130° F., morepreferably about 100° F. to 120° F. for about 0.1 to five seconds; meansfor transforming the low viscosity mixture under non vacuum conditionsand under condition of non agitation or non mixing at a temperature ofabout 65° F. to 120° F. for about 15 to 30 minutes into a high viscositynon Newtonian paste or cream like material which is subsequentlydeaerated under vacuum for less than three seconds to form a dentifricewhich is subsequently passed through a screen pack of less than about0.01 inches, for example, 0.007 inches.

Another object of the instant invention is to provide a non-Newtoniandentifrice, and means for deaerating and polishing the non-Newtoniandentifrice under a vacuum of about 25 inches to about 30 inches forabout 0.05 to about 2 seconds to form the non-Newtonian paste or creamlike material.

Accordingly, it is an object of the present invention to provide acontinuous process for the manufacture of a non-Newtonian paste or creamlike material having enhanced flavor and improved product stability asevidenced by a G' value over a strain range of 0.1 to 0.5 percent at 6.3radians/second of at least about 4,000 dynes/sq. cm, and a complexviscosity over a strain range of about 0.1 to 0.5 seconds at 6.3radians/second of at least about 700 Pascal-seconds. The improvementprocess provides energy input savings, labor cost savings as well asforming a composition having improved non-Newtonian flowcharacteristics, and enhanced flavor characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic flow diagram of the instant continuousprocess for the manufacture of an improved non-Newtonian paste or creamlike material having enhanced flavor.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates to a continuous process for themanufacture of a high viscosity non-Newtonian paste or cream likematerial which comprises the steps of: means for forming undernon-vacuum conditions at a temperature of about 90° F. to 130° F. andmore preferably about 100° F. to 120° F. a first low viscosityhomogenous slurry of at least one non-aqueous solvent and a gellingagent; means for forming a second low viscosity homogenous slurry undernon-vacuum conditions at a temperature of about 90° F. to 130° F.,wherein the second homogenous slurry includes water and at least oneadditive ingredient; means for forming a low viscosity mixture of thefirst slurry and the second slurry by high shear mixing under non vacuumconditions and means for transforming the low viscosity mixture undernon agitation conditions at a temperature of about 65° F. to 120° F. forabout 15 to 30 minutes into a non Newtonian paste or cream likematerial, means for deaerating under vacuum for less than three secondsthe non Newtonian paste or cream like material and means for filteringthe non Newtonian paste or cream like material through a screen pack ofless than about 0.01 inches.

The process of the instant invention is depicted in FIG. 1. A firstmixer tank 10 contains a first mixing means 12 such as a stirrer. Atleast one first hopper 14 is supplied for solid materials 11, whereinthe first hopper 14 communicates with the first mixing tank 14 through afirst line 15. A first vessel 18 is supplied for the delivery of waterto the first mixing tank 10, wherein the first vessel 18 communicateswith the first mixing tank 10 through a second line 17. A second mixingtank 20 containing a second mixing means 22 such as a stirrer. At leastone second hopper 24 is supplied for the solid gelling agent 21, whereinthe second hopper 24 communicates with the second mixing tank 20 througha third line 25. A second vessel 28 is supplied for the delivery of anon aqueous solvent to the second mixing tank 20, wherein the secondvessel 28 communicates with the second mixing tank 20 through a fourthline 27. Fifth 30 and sixth 32 lines are in fluid communication with thefirst 10 and second 20 mixing tanks respectively and the fifth 30 andsixth 32 lines are in fluid communication with an inlet of in linestatic mixer 34. A seventh line 36 is in fluid communication with theoutlet of the in line static mixer 34 and a maturing tank 38. An eighthline 40 is in fluid communication with the maturing tank 38 and an inletof a Versator 42 which has a vacuum means 44. The Versator 42 is incommunication with a holding tank 46 through a ninth line 48, whereinthe holding tank 46 is in communication with an inlet of pump 51 througha tenth line 52. A discharge line 54 has a screen pack 56 disposedtherein, wherein the discharge line 54 is in communication with theoutlet of pump 51. The other end of the discharge line 54 dischargesinto a storage tank 58. The mixing tank 20 provides the means forpreparing a second low viscosity slurry of water and the solid andliquid ingredients of the cream or paste like material except for thenonaqueous solvent and gelling agent, wherein the concentration of theingredients is about 36 to about 80 weight percent. Mixing occurs undernon vacuum conditions at atmospheric conditions in the mixing tank 20 ata temperature of about 90° F. to about 130° F. for about 5 to 30 minutesat a mixing speed of about 100 to 400 rpms, more preferably about 200 to300 rpms. The mixing tank 10 provides a means for forming a first lowviscosity slurry of the non aqueous and gelling agent, wherein theconcentration of the gelling agent is about 9 to 29 weight percent, morepreferably about 10 to 26 weight percent. The mixing in the mixing tank10 occurs under non vacuum conditions at atmospheric conditions forabout 5 to 30 minutes at a temperature of about 90° F. to 130° F. at amixing speed of about 100 to 400 rpms, more preferably about 200 to 300rpms. The means for forming the low viscosity mixture of the lowviscosity slurry of water and the liquid and solid ingredients and thelow viscosity slurry of the non aqueous solvent and gelling agentcomprises passing the two low viscosity slurry through an in line staticmixer 34 under non vacuum conditions at atmospheric pressure at atemperature of about 90° F. to 130° F., wherein the residence time inthe in line static mixer 34 is about 0.05 to 3.0 seconds, and morepreferably about 0.05 to 2.0 seconds. The means for transforming the lowviscosity mixture into a high viscosity non Newtonian mixture comprisesholding the low viscosity mixture in a maturing tank 38 under non vacuumcondition without mixing or agitation at a temperature of about 100° F.to 120° F. for about 15 minutes to 60 minutes more preferably about 15to 30 minutes, under non vacuum conditions at atmospheric pressure. Byemploying conditions of non vacuum and non agitation or non mixing amore uniformly hydrated product with improved non Newtonian propertiesand less encapsulated air is formed as compared to products formed underconditions of agitation and/or vacuum. If heating and cooling andagitation is employed during the hydrating step a poorer polymericmatrix is formed, wherein there is insufficient wetting andincorporation of the solid particles into the polymeric matrix asillustrated in U.S. Pat. No. 2,751,328. A slow hydration step at anessentially constant temperature under non mixing conditions as in theinstant process permits the maximization of the formation of thepolymeric matrix which ensures proper wetting and incorporation of thesolid particles into the polymeric matrix. The means for deaerating andpolishing the non Newtonian mixture into the non Newtonian cream orpaste like material having a G' value over a strain range of 0.1 to 0.5percent at 6.3 radians/second of at least about 4,000 dynes/sq.cm, and acomplex viscosity over a strain range of 0.1 to 0.5% at 6.3radians/second of at least about 700 Pascal-seconds comprises passingthe non Newtonian mixture through a Versator 42 at a temperature ofabout 80° F. to about 120° F. under a vacuum of about 690 to about 720mm, wherein the residence time in the Versator 42 is about 0.05 to about3.0 seconds, more preferably about 0.1 to about 2.0 seconds. The nonNewtonian cream or paste like materials such as a toothpaste is passedthrough a 0.007 inch filter screen pack 56 to form the final product.The non-Newtonian cream or paste like material such as a cosmetic,toothpaste or dental cream having a G' value over a strain range of 0.1to 0.5 percent at 6.3 radians/second of at least about 4,000dynes/sq.cm, more preferably at least about 5,000 dynes/sq.cm, and mostpreferably at least about 5,500 dynes/sq. cm and a complex viscosityover a strain range of 0.1 to 0.5 percent at 6.3 radians/second of atleast about 700 Pascal-seconds, more preferably about 800 Pascal-secondsand most preferably about 900 Pascal-econds comprises approximately byweight: a) 0 to 70%, more preferably 1 to 40% of at least one nonaqueous solvent;

b) 0.05 to 5.0%, more preferably 0.1 to 3.5% of at least one gellingagent, one of which gelling agents must be a crosslinked metalneutralized anionic polymer acid gelling agent;

c) 0 to 50%, more preferably 0.5 to 50%, and most preferably 0.5 to 40%of at least one polishing agent;

d) 0 to 30%, more preferably 0.5 to 25% of a bodying or swelling agent;

e) 0.05 to 3%, more preferably 0.1 to 2.5% of at least one surfaceactive material;

f) 0 to 1.5%, more preferably 0.15 to 1.25% of a flavoring agent;

g) a fluoride containing compound in a sufficient amount to provide 0 to5,000 ppms of fluoride ions;

h) 0 to 0.75%, more preferably 0.1 to 0.5% of a water insolublenoncationic antibacterial agent;

i) 0 to 3%, more preferably 0.1 to 2.5% of a film polymeric material;

j) 0 to 5%, more preferably 0.5 to 4% at least one anticalculus agent;

(k) 0 to 5% of an alkali metal phosphate; and

(l) water.

The instant compositions show a two to five fold increase in their G'values and complex viscosities over the same formula produced by a batchprocess which have a G' value of 2,000 dynes/sq.cm and a complexviscosity of 400 Pascal-seconds.

In oral preparations such as a dentifrice, an orally acceptable vehicleincluding a water phase with a non aqueous solvent being usuallypresent. In the present invention, the water and non aqueous solventliquid phase usually comprises at least about 10% by weight of the oralpreparation. One typical non aqueous solvent is preferably propyleneglycol, which is present as a portion of the non aqueous solvent tosolubilize the substantially water-insoluble noncationic antibacterialagent. The remainder of the non aqueous solvent is typically glycerineand/or sorbitol. Water is present typically in amount of at least about3% by weight and glycerine and/or sorbitol typically total about 6.5-75%by weight of the oral preparation, more typically about 10-75%, and,together with the solubilizing non aqueous solvent, the essential nonaqueous solvent components typically amount to about 7-80% by weight ofthe oral preparation. Reference hereto to sorbitol refers to thematerial typically as available commercially in about 70% aqueoussolutions.

Besides the solubilizing non aqueous solvent, propylene glycol, othersolubilizing agents which do not adversely affect the antibacterialactivity in oral preparations may be used. These are dipropylene glycol,methyl cellosolve, ethyl cellosolve, olive oil, castor oil, amylacetate, ethyl acetate, glycerol tristerate and benzyl benzoate.

Toothpastes, creams and gels typically contain a natural or syntheticthickener, bodying or gelling agent in proportions of about 0.1 to about10, preferably about 0.5 to about 5%. A suitable thickener is synthetichectorite, a synthetic colloidal magnesium alkali metal silicate complexclay available for example as Laponite (e.f. CP, SP 2002,D) marketed byLaporte Industries Limited. Laponite D analysis shows, approximately byweight, 58.00% SiO₂, 25.40% MgO, 3.05% Na₂ O, 0.98% Li₂ O, and somewater and trace metals. Its true specific gravity is 2.53 and it has anapparent bulk density (g./ml. at 8% moisture) of 1.0.

Other suitable thickeners include Irish moss, i-carrageenan, gumtragacanth, starch polyvinylpyrrolidone, hydroxyethy-propylcellulose,hydroxbutyl methyl cellulose, hydroxypropyl methyl cellulose,hydroxyethyl cellulose (e.g. available as Natrosol), sodiumcarboxymethyl cellulose, and colloidal silica such as those available asfinely ground Syloid (244) and Sylodent 15.

Organic surface-active agents are used in the compositions of thepresent invention to achieve increased prophylactic action, assist inachieving thorough and complete dispersion of the anticalculus agent, ifpresent, throughout the oral cavity, and render the instant compositionsmore cosmetically acceptable. The organic surface-active material ispreferably anionic, nonionic or ampholytic in nature, and it ispreferred to employ as the surface-active agent a detersive materialwhich imparts to the composition detersive and foaming properties.Suitable examples of anionic surfactants are water-soluble salts ofhigher fatty acid monoglyceride monosulfates, such as the sodium salt ofthe monosulfated monoglyceride of hydrogenated coconut oil fatty acids,higher alkyl sulfates such as a sodium lauryl sulfate, alkyl arylsulfonates such as sodium dodecyl benzene sulfonate, higher alkylsulfoacetates, higher alkyl sulfoacetates higher fatty acid esters of1.2 dihydroxy propane sulfonate, and the substantially saturated higheraliphatic acyl amides of lower aliphatic amino carboxylic acidcompounds, such as those having 12 to 16 carbons in the fatty acid,alkyl or acyl radicals, and the like. Examples of the last mentionedamides are N-lauroyl sarcosine, and the sodium, potassium, andethanolamine salts of N-lauroyl, N-myristoyl, or N-palmitoyl sarcosinewhich should be substantially free from soap or similar higher fattyacid material. The use of these sarcosinate compounds in the oralcompositions of the present invention is particularly advantageous,since these materials exhibit a prolonged and marked effect in theinhibition of acid formation in the oral cavity due to carbohydratebreakdown in addition to exerting some reduction in the solubility oftooth enamel in acid solutions. Examples of water-soluble nonionicsurfactants are condensation products of ethylene oxide with variousreactive hydrogen-containing compounds reactive therewith having longhydrophobic chains (e.g. aliphatic chains of 12 to 20 carbon atoms),which condensation products ("ethoxamers") contain hydrophilicpolyoxyethylene moieties, such as condensation products of poly(ethylene oxide) with fatty acids, fatty alcohols, fatty amides,polyhydric alcohols (e.g. sorbitan monostearate) and polypropyleneoxide(e.g. Pluronic materials).

A surface active agent is typically present in the composition in amountof about 0-5% by weight, more preferably about 0.05 to 3.5 wt. %. Thesurface active agent can assist in the dissolving of the noncationicantibacterial agent and thereby diminish the amount of solubilizing nonaqueous solvent which is needed.

When the composition of this invention is a dental composition, thecomposition generally contains a dentally acceptable polishing material.Examples of polishing materials are water-insoluble sodiummetaphosphate, potassium metaphosphate, tricalcium phosphate, dehydratedcalcium phosphate, anhydrous dicalcium phosphate, calcium pyrophosphate,magnesium orthophosphate, trimagnesium phosphate; calcium carbonate,aluminum silicate, zirconium silicate, silica, bentonite, and mixturesthereof.

Other suitable polishing material include the particulate thermosettingresins described in U.S. Pat. No. 3,070,510 such as melamine, phenolic,and urea-formaldehyde, and cross-linked polyepoxides and polyester.Preferred polishing materials include-crystalline silica having particlesized of up to 5 microns, a mean particle size of up to 1.1 microns, anda surface area of up to 50,000 cm.² /gm., silica gel or colloidalsilica, and complex amorphous alkali metal aluminosilicate.

When visually clear or opacified gels are employed, a polishing agent ofcolloidal silica, such as those sold under the trademark SYLOID asSyloid 72 and Syloid 74 or under the trademark SANTOCEL as Santocel 100or alkali metal almuino-silicate complexes are particularly useful,since they are consistent with gel-like texture and have refractiveindices close to the refractive indices of gelling agent-liquid(including water and/or humectant) systems commonly used in dentifrices.

Many of the so-called "water-insoluble" polishing materials are anionicin character and also include small amounts of soluble material. Thus,insoluble sodium metaphosphate may be formed in any suitable manner asillustrated by Thorpe's Dictionary of Applied Chemistry, Volume 9, 4thEdition, pp. 510-511. The forms of insoluble sodium metaphosphate knownas Madrell's salt and Kurrol's salt are further examples of suitablematerials.

These metaphosphate salts exhibit only a minute solubility in water, andtherefore are commonly referred to as insoluble metaphosphates (IMP).There is present therein a minor amount of soluble phosphate material asimpurities, usually a few percent such as up to 4% by weight. The amountof soluble phosphate material, which is believed to include a solublesodium trimetaphosphate in the case of insoluble metaphosphate, may bereduced or eliminated by washing with water if desired. The insolublealkali metal metaphosphate is typically employed in powder form of aparticle size such that no more than about 1% of the material is largerthan 37 microns.

The polishing material is generally present in the dental cream paste orgel compositions in weight concentrations of 0% to 50%.

The sources of fluoride ions in dental compositions, if present, orfluorine-providing component, if present, as anti-caries as well arewell known in the art as anti-caries agents. These compounds may beslightly soluble in water or may be fully water-soluble. They arecharacterized by their ability to release fluoride ions in water and byfreedom from undesired reaction with other compounds of the oralpreparation. Among these materials are inorganic fluoride salts, such assoluble alkali metal, alkaline earth metal salts, or example, sodiumfluoride, potassium fluoride, ammonium fluoride, calcium fluoride, acopper fluoride such as cuprous fluoride, zinc fluoride, bariumfluoride, sodium fluorosilicate, ammonium fluorosilicate, sodiumfluorizirconate, sodium fluorozirconate, sodium monofluorphosphate,alaminum mono-and difluorophosphate, and fluorinated sodium calciumpyrophosphate. Alkali metal and tin fluorides, such as sodium andstannous fluorides, sodium monofluorophosphate (MFP) and mixturesthereof, are preferred.

The amount of fluorine-providing compound is dependent to some extentupon the type of compound, its solubility, and the type of oralpreparation, but it must be a non-toxic amount, generally about 0.0005to about 3.0% in the preparation. In a dentifrice preparation, e.g.dental gel and toothpaste paste or cream, an amount of such compoundwhich releases up to about 5,000 ppm of fluoride ion by weight of thepreparation is considered satisfactory. Any suitable minimum amount ofsuch compound may be used, but it is preferable to employ sufficientcompound to release about 300 to about 5,000 ppms, more preferably 800to 2,000 ppms of fluoride ion.

Typically, in the cases of alkali metal fluorides, this component ispresent in an amount of 0 to 5% by weight, based on the weight of thepreparation, and preferably in the range of about 0.05% to about 2.5%.In the case of sodium monofluorphosphate, the compound may be present inan amount of about 0.1 to 8%, more preferably about 0.35 to 7.6%.

The composition of the instant invention can contain an effectiveantiplaque amount of a substantially water insoluble noncaitonicantibacterial agent selected from the group consisting essentially ofhalogenated diphenyl ethers and phenolic compounds and about 0 to about3% by weight of a synthetic anionic polymeric polycarboxylate having amolecular weight of about 1,000 to 1,000,000, wherein the non aqueoussolvent includes a solubilizing agent selected from the group consistingof propylene glycol, dipropylene glycol, methylcellosole, ethylcellosolve, olive oil, castor oil, amyl acetate, ethyl acetate, glyceroltristearate and benzyl benzoate which must be mixed with at least one ofglycerine and/or sorbitol. The amount of the solubilizing agent must besufficient to dissolve the antibacterial agent.

Typical examples of water insoluble noncationic antibacterial agentswhich are particularly desirable from considerations of antiplaqueeffectiveness, safety and formulation are:

Halogenated Diphenyl Ethers

2',4,4'-trichloro-2hydroxidiphenyl ether (Triclosan)

2,2'dihydroxy-5,5'-dibromo-diphenyl ether.

Phenolic Compounds

(including phenol and its homologs, mono-and poly-alkyl and aromatichalophenols, resorcinol and its derivatives, bisphenolic compounds andhalogenated salicylanilides)

Phenol and its Homologs

Phenol

Methyl - Phenol

Methyl - Phenol

Methyl - Phenol

Ethyl - Phenol

2,4-Dimethyl - Phenol

2,5-Dimethyl - Phenol

3.4-Dimethyl - Phenol

2.6-Dimethyl - Phenol

4-n-Propyl - Phenol

4-n-Butyl - Phenol

4-n-Amyl - Phenol

4-Tert-Amyl - Phenol

4-n-Hexyl - Phenol

4-n-Heptyl - Phenol

Mono- and Poly-Alkyl and Aromatic Halophenols Methyl - p-Chlorophenol

Ethyl - p-Chlorophenol

n-Propyl - p-Chlorophenol

n-Butyl- p-Chlorophenol

n-Amyl - p-Chlorophenol

sec-Amyl - p-Chlorophenol

n-Hexyl - p-Chlorphenol

Cyclohexyl - p-Chlorophenol

n-Heptyl - p-Chlorophenol

n-Octyl - p-Chlorophenol

O-Chlorophenol

Methyl - o-Chlorophenol

Ethyl - o-Chlorophenol

n-Propyl - o-Chlorophenol

n-Butyl - o-Chlorophenol

n-Amyl - o-Chlorophenol

tert-Amyl - o-Chlorophenol

n-Hexyl - o-Chlorophenol

n-Heptyl - o-Chlorophenol

p-Chlorophenol

o-Benzyl - p-Chlorophenol

o-Benzyl m-methyl - p-Chlorophenol

o-Phenylethyl - p-Chlorophenol

o-Phenylethyl-m-methyl - p-Chlorophenol

3-Methyl - p-Chlorophenol

3.5 Dimethyl - p-Chlorophenol

6-Ethyl-3-methyl - p-Chlorophenol

6-n-Propyl-3-methly - p-Chlorophenol

6-iso-Propyl-3-methyl - p-Chlorophenol

2-Ethyl-3,5-dimethyl - p-Chlorophenol

6-sec Buty-3-methyl - p-Chlorophenol

2-iso-Propyl -3,5-dimethyl - p-Chlorophenol

6-Diethylmethyl-3-methyl - p-Chlorophenol

6-iso-Propyl-2-ethyl-3-methyl- p-Chlorophenol

2-sec Amyl 3,5-dimethyl - p-Chlorophenol

2-Diethylmethyl-3,5-dimethyl - p-Chlorophenol

6-sec Octyl-3-methyl - p-Chlorophenol

p-Bromophenol

Methyl - p-Bromophenol

Ethyl - p-Bromophenol

n-Propyl - p-Bromophenol

n-Butyl - p-Bromophenol

n-Amyl - p-Bromophenol

sec-Amyl - p-Bromophenol

n-Hexyl - p-Bromophenol

Cyclohexyl - p-Bromophenol

o-Bromophenol

tert-Amyl - o-Bromophenol

n-Hexyl - o-Bromophenol

n-Propyl-m.m-Dimethyl - o-Bromophenol

2-Phenyl Phenol

4-Chloro-2-methyl phenol

4-chloro-3-methyl phenol

4-chloro-3,5-dimethyl phenol

4,4-dichloro-3,5-diaethyophenol

3,4,5,6-terabromo-2-methylphenol

5-methyl-2-pentylphenol

4-isopropyl-3-methylphenol

5-chloro-2-hydroxydiphenylemthane

Resorcinol and its Derivatives

Resorcinol

Methyl - Resorcinol

Ethyl - Resorcinol

n-Propyl - Resorcinol

n-Buryl - Resorcinol

n-Amyl - Resorcinol

n-Hexyl - Resorcinol

N-Heptyl - Resorcinol

n-Octyl - Resorcinol

n-Nonyl - Resorcinol

Phenyl - Resorcinol

Benzyl - Resorcinol

Phenylethyl - Resorcinol

Phenylpropyl - Resorcinol

P-Chlorobenzyl - Resorcinol

5-Chloro - 2,4-Dihydroxydiphenyl Methane

4'-Chloro -2,4-Dihydroxydiphenyl Methane

5-Bromo -2,4-Dihydroxydiphenyl Methane

4'-Bromo - 2,4-Dihydroxydiphenyl Methane

4'-Bromo -2,4-Dihydroxydiphenyl Methane

Bisphenolic Compounds

2,2'-methylene bis (4-chlorophenol)

2.2'-methylene bis (3,4,6-trichlorophenol)

2,2'-methylene bis(4-chloro-6-bromophenol)

bis (2-hydroxy-3,5 -dichlorophenyl) sulfide

bis (2-hydroxy-5-chlorobenzyl) sulfide

If a noncationic antibacterial agent is used in the dental composition,it is present in the oral composition in an effective antiplaque amount,typically about 0 to about 0.75% by weight, more preferably about 0.1 toabout 0.50%. The antibacterial agent is substantially water-insoluble,meaning that its solubility is less than about 1% by weight in water at25° C. and may be even less than about 0.1%.

The preferred halogenated diphenyl ether is triclosan. The preferredphenolic compounds are hexyl resorcinol and 2,2'-methylenebis(4-chloro-6-bromophenol). The most preferred antibacterial antiplaquecompound is triclosam. Triclosan is disclosed in aforementioned U.S.Pat. No. 4,022,880 as an antibacterial agent in combination with ananticalculas agent which provides zinc ions. It is also disclosed as anantiplaque agent in a dentifrice formulated to contain a lamellar liquidcrystal surfactant phase having a lamellar spacing of less than about6.0 mm and which may optionally contain a zinc salt in publishedEuropean Patent Application No. 0161898 of Lane et al and in adentifrice containing zinc citrate trihydrate in published EuropeanPatent Application No. 0161899 to Saxton et al. Synthetic anionicpolymeric polycarboxylate having a molecular weight of about 1,000 toabout 1,000,000, preferably about 30,000 to about 500,000, have beenused in optimizing anticalculus effectiveness of linear molecularlydehydrated polyphosphate salts, as disclosed in U.S. Pat. No. 4,627,977to Gaffar et al. It is also effective to enhance delivery and retentionof the nonionic antibacterial, antiplaque agent to dental surfaces.

The synthetic anionic polymer such as a polymeric polycarboxylate is aninhibitor of alkaline phosphatase enzyme. Synthetic anionic polymericpolycarboxylates and their complexes with various cationic germicides,zinc and magnesium have been previously disclosed as anticalculus agentsper se in, for example U.S. Pat. No. 3,429,963 to Shedlovsky; U.S. Pat.No. 4,152,420 to Gaffar: U.S. Pat. No. 3,956,480 to Dichter et al; U.S.Pat. No. 4,138,477 to Gaffar; and U.S Pat. No. 4,183,914 to Gaffar etal. It is to be understood that the synthetic anionic polymericpolycarboxylates disclosed in these several patents are operative in thecompositions and process of this invention and such disclosures are tothat extent incorporated herein by reference thereto.

The synthetic anionic polymeric polycarboxylates employed hereininforming the gel composition are well known, being employed in the formof their neutralized water soluble alkali metal (e.g. potassium andpreferably sodium) or ammonium salts. Preferred are 1:4 to 4:1copolymers of maleic anhydride or acid with another polymerizableethylenically unsaturated monomer, preferably vinyl ether (maleicanhydride) having a molecular weight (M.W.) of about 30,000 to about1,000,000, most preferably about 30,000 to about 500,000. Thesecopolymers are available for example as Gantrez AN 139 (M.W. 500,000),A.N. 119 (M.W. 250,000); and preferably S-97 Pharmaceutical Grade (M.W.70,000), of GAF Corporation. The term "synthetic" is intended to excludeknown thickening or gelling agents-comprising carboxymethylcellulose andother derivatives of cellulose and natural gums.

Other operative polymeric polycarboxylates include those disclosed inU.S. Pat. No. 3,956,480 referred to above, such as the 1:1 copolymers ofmaleic anhydride with ethyl acrylate, hydroxyethyl methacrylate,N-vinyl-2-pyrollidone, or ethylene, the latter being available forexample as Monsanto EMA No. 1103, M.W. 10,000 and EMA Grade 61, and 1:1copolymers of acrylic acid with methyl or hydroxethyl methacrylate,methyl or ethyl acrylate, isobutyl vinyl ether of N-vinyl-2-pyrrolidone.

Additional operative polymeric polycarboxylates disclosed in abovereferred to U.S. Pat. Nos. 4,138,477 and 4,183,914, include copolymersof maleic anhydride with styrene, isobutylene or ethyl vinyl ether,polyacrylic, polyitaconic and polymaleic acids, and sulfoacrylicoligomers of M.W. as low as 1,000, available as Uniroyal ND.2.

Suitable generally are polymerized olefinically or ethylenicallyunsaturated carboxylic acids containing an activated carbon-to-carbonolefinic double bond and at least on carboxyl group, that is, an acidcontaining an olefinic double bond which readily functions inpolymerization because of its presence in the monomer molecule either inthe alpha-beta position with respect to a carboxyl group or as part of aterminal methyle grouping. llustrative of such acids are acrylic,methacrylic, ethacrylic, alpha-chloroacrylic, crontonic, betaacryloxypropionic, sorbic, alpha-chlorsorbic, cinnamic, beta-styrilacrylic,muconic, itaconic, citraconic, mesaconic, glutaconic, aconitie,alpha-phenylacrylic, 2-benzyl acrylic, 2-cyclohexylacrylic, angelic,mbellic, fumaric, maleic acids and anhydrides. Other different olefinicmonomers copolymeizable with such carboxylic monomers includevinylacetate, vinyl chloride, dimethyl maleate and the like. Copolymerscontain sufficient carboxylic salt groups for water-solubility.

Also, useful herein are so-called carboxyvinyl polymers disclosed astoothpaste components in U.S. Pat. No. 3,980,767 to Chown et al; U.S.Pat. No. 3,935,306 to Roberts et al; U.S. Pat No. 3,919,409 to Perla etal; U.S. Pat. No. 3,911,904 to Harrison, and U.S. Pat. No. 3,711,604 toColodney et al. They are commercially available for example under thetrademarks Carbopol 934, 940 and 941 of BFGoodrich, these productsconsisting essentially of a collodially water-soluble polymer ofpolyacrylic acid crosslinked with from 0.75% to 2.0% of polyallylsucrose of polyallyl pentaerythritol as cross linking agent.

The synthetic anionic polymeric polycarboxylate component is mainly ahydrocarbon with optional halogen and oxygen containing substituents andlinkages as present in for example ester, ether and OH groups, and whenpresent is employed in the instant compositions in approximate weightamounts of about 0.005 to about 4%, preferably about 0.05 to about 3%,more preferably about 0.1 to about 2%. Amounts in the upper portions ofthese ranges are typically employed in dentifrice compositions typicallycontaining a dental abrasive and used in conjunction with brushing ofthe teeth, e.g. tooth pastes (including creams), gels, powders andtablets. Amounts in excess of these ranges may be employed forthickening or gelling purposes.

Without being bound to a theory, it is believed that the polymericpolycarboxylate is an anionic film forming material and is thought toattach to tooth surfaces and form a continuous film over the surfaces,thereby preventing bacterial attachment to tooth surfaces. It ispossible that the noncationic antibacterial agent forms a complex withthe polycarboxylate, thus forming a film of a complex of the two overtooth surfaces. The film forming property of the polycarboxylate and theenhanced delivery and film forming property of the polycarboxylate andthe enhanced delivery and retention of the antibacterial agent on toothsurfaces due to the polycarboxylate appears to make tooth surfacesunfavorable for bacterial accumulation particularly since the directbacteriostatic action of the antibacterial agent controls bacterialgrowth. Therefore, through the combination of three modes of actions: 1)enhanced delivery, 2) long retention time on tooth surfaces and 3)prevention of bacterial attachment to tooth surfaces, the oralcomposition is made efficacious for reducing plaque.

In accordance with a further aspect of the invention anticalculusproperties may also be provided to the oral composition by the inclusionof a molecularly dehydrated polyphosphate salt in the compositions madeby the continuous process of the instant invention.

The linear molecularly dehydrated polyphosphate salts operative hereinas anticalculus agents are well known, being generally employed in theform of their wholly or partially neutralized water soluble alkali metal(e.g. potassium and preferable sodium) or ammonium salts, and anymixtures thereof. Representative examples include sodiumhexametaphosphate, sodium tripolyphosphate, disodium diacid, trisodiummonoacid and tetrasodium pyrophosphates and the like. Linearpolyphosphates correspond to (NaPO₃)n where n is about 2 to about 125.They are generally employed in the instant oral compositions inapproximate weight amounts of about 0.1 to about 7%, preferably about 1to about 7%, more preferably about 2 to about 7%. When n is at least 3in (NaPO₃)n, the polyphosphates are glassy in character.

Particularly desirable anticalculus agents are tetraalkali metalpyrophosphates, including mixtures thereof, such as tetrasodiumpyrophosphate, tetrapotassium pyrophosphate and mixtures thereof. Ananticalculus agent comprising about 4.3% to about 7% by weight of theoral compositions is especially preferred wherein the weight ratio oftetrapotassium pyrophosphate to tetrasodium pyrophosphate is from about4.3:2.7 to about 6:1 is especially preferred.

In order to optimize the anticalculus effectiveness of the oralcomposition, inhibitors against enzymatic hydrolysis of thepolyphosphate can be desirably present. The synthetic anionic polymericpolycarboxylate as described is one such agent. The other is an amountof a fluoride ion source sufficient to supply about 0 to about 5,000ppms, more preferably about 25 ppms to about 5,000 ppms of fluorideions. The fluoride ion source may be present even when the polyphosphateanticalculus agent is not, since it also provides anticarieseffectiveness.

Various other materials may be incorporated in the oral preparations ofthis invention made by the instant continuous process such as whiteningagents, preservatives, silicones, chlorophyll compounds and/orammoniated material such as urea, diammonium phosphate, and mixturesthereof. These adjuvants, where present, are incorporated in thepreparations in amounts which do not substantially adversely affect theproperties and characteristics desired. Significant amounts of zinc,magnesium and other metal salts and materials, generally soluble, whichwould complex with active components of the instant invention are to beavoided.

Any suitable flavoring or sweetening material may also be employed.Examples of suitable flavoring constituents are flavoring oils, e.g. oilof spearmint, peppermint, wintergreen, sassafras, clove, sage,eucalyptus, marjoram, cinnamon, lemon, and orange, and methylsalicylate. Suitable sweetening agents include sucrose, lactose,maltose, xylitol, sodium cyclmate, perillartine, AMP (aspartyl phenylalanine, methyl este) saccharine and the like. Suitably, flavor andsweetening agents may together comprise from about 0.1% to about 5% ormore of the preparation.

The pH of such liquid and other preparations of the invention isgenerally in the range of about 4.5 to about 9 to about 10 and mostpreferably about 6.5 to about 7.5. The pH can be controlled with acid(e.g. citric acid or benzoic acid) or base (e.g. sodium hydroxide) orbuffered (as with sodium citrate, benzoate, carbonate, or bicarbonate,disodium hydrogen phosphate, sodium dihydrogen phosphate, etc.).

The following examples are further illustrative of the nature of thepresent invention, but it is understood that the invention is notlimited thereto. All amounts and proportions referred to herein and inthe appended claims are by weight, unless otherwise indicated.

EXAMPLE 1

The following paste composition was made according to the followingprocedure.

    ______________________________________                                                           Weight %                                                   ______________________________________                                        Water                21.379                                                   Dicalcium phosphate Anhydrous                                                                      3.912                                                    Sorbitol             12.715                                                   Sodium Monoflurophosphate                                                                          0.758                                                    Dicalcium Phosphate (dihydrate)                                                                    45.187                                                   Sodium Saccharin     0.30                                                     Sodium Lauryl Sulfate                                                                              2.328                                                    Flavor               1.565                                                    Sodium Lauryol Sarcosinate                                                                         0.217                                                    Glycerine            10.759                                                   Viscarin Gelling Aent                                                                              1.050                                                    ______________________________________                                    

Viscarin was added into the first mixing tank 10 containing glycerine ata temperature of 70° F. and at 760 mm, and the mixture was mixed for 10minutes to form the first low viscosity slurry.

Heated water at a temperature of 160° F. water was added to the secondmixing tank 20. Sorbitol at 130° F. was added to mixing tank 20 withmixing and a blend of the sodium monofluoro- phosphate, anhydrous sodiumsaccharin and the sodium lauryl sulfate was also added to the mixingtank 20 to form a second low viscosity slurry and mixing at 125°-130° F.was continued for 5-10 minutes. The dicalcium phosphate was taken addedto the mixing tank 20 at a temperature of 120°-125° F. and at 760 mm.The flavor was then added to the mixing tank 10 with mixing and then thesodium lauryol saccosinate was added at a temperature of 120° F. at 760mm to the mixing tank 10 with mixing for 15-20 minutes finish formingthe first low viscosity slurry.

The first and second low viscosity slurries were pumped into an in-linestatic mixer 34 at a temperature of 120° F. at 760 mm to form a lowviscosity mixture which was then pumped into a maturing tank 38, whereinthe low viscosity mixture was maintained without mixing under non vacuumconditions at a temperature of 120° F. for 30 minutes and the lowviscosity mixture was transformed into a high viscosity non-Newtonianmixture.

The non Newtonian mixture was feed into a Versator 42 at a temperatureof 120° F. with a vacuum of 710 mm, wherein the non Newtonian mixturewas deaerated for less than three seconds and polished to form the nonNewtonian paste composition. The non Newtonian was then feed through ascreen pack of 0.007 inches to the holding tank.

    ______________________________________                                        Test Results                                                                  ______________________________________                                        pH                       7.3                                                  Specific gravity         1.35                                                 Complex viscosity.sup.1 at 6.3 radians/second                                                          1,000 Pascal                                         over a strain range of 0.1 to 0.5 percent                                                              seconds                                              G'.sup.2 over a strain range of 0.1 to 0.5 percent                                                     6,000 Pascal                                         at 6.3 radians/second                                                         ______________________________________                                         .sup.1 and .sup.2 - Testing on CarriMed rheometer                        

The same formula was made by the following batch process. Glycerine wascharged into the Gel Mix Tank. Viscarin, Sodium Monofluoride Phosphate,and Sodium Saccharin were added and mixed for 5-10 minutes. Sorbitol andD.I Water (140° F.) are added to Gel mix Tank and were heated to150°-160° F. Once at temperature, the batch was mixed for 20 minutes andthen was transferred to the vacuum mixer and the cooling water wasstarted in the jacket. Dicalcium Phosphate, Dicalcium PhosphateAnhydrous and flavor (batch temperature must be below 100° F.) wereadded while mixing at high speed. A vacuum (27.5" minimum) was pulledand mixing was continued for 15 minutes. The vacuum was released and themixer was stopped and Sodium Lauryl Sulfate and Sodium LauryolSarcosinate were then added. A vacuum (27.5" minimum) was pulled andmixing was continued for 10 minutes. The mixer was stopped and thevacuum was released. The product was pumped through a 0.007 inch screen.

    ______________________________________                                        Test Results                                                                  ______________________________________                                        pH                       7.3                                                  Specific gravity         1.34                                                 Complex viscosity over a strain range of 0.1                                                           400 Pascal                                           to 0.5 percent at 6.3 radians/second                                                                   seconds                                              G' over a strain range of 0.1 to                                                                       2,000 dynes/                                         0.5 percent at 6.3 radians/second                                                                      sq. cm.                                              ______________________________________                                    

What is claimed is:
 1. A continuous process for preparing a nonNewtonian paste or cream like material which comprises the steps of:(a)forming under non vacuum conditions at a temperature of 90° F. to 130°F. a first low viscosity homogenous slurry of at least one non aqueoussolvent and a bodying or gelling agent; (b) forming a second lowviscosity homogenous slurry under non vacuum condition at a temperatureof 90° F. to 130° F., said second low viscosity homogenous slurryincludes water and at least one additive ingredient; (c) forming a lowviscosity mixture of said first low viscosity slurry and said second lowviscosity slurry by high shear mixing under non vacuum conditions at atemperature of 90° F. to 130° F. for 0.1 to 5 seconds; (d) transformingsaid low viscosity mixture in a maturing tank under non vacuumconditions at a temperature of about 100° F. to about 120° F. for about15 to abut 60 minutes into a high viscosity, non Newtonian mixturehaving less encapsulated air at atmospheric pressure and without mixingor agitation; and; (e) deaerating said non Newtonian mixture undervacuum conditions at a temperature of 80° F. to 120° F. for a period of0.05 to 3 seconds to form said non-Newtonian paste or create likematerial.
 2. A process according to claim 1, wherein at least one saidadditive ingredient is selected from the group consisting essentially ofat least one polishing agent, an alkali metal phosphate, a polymericmaterial, a fluoride containing compound, a surface active compound, aflavoring agent, a bodying or gelling agent, at least one anticalculusagent, and a water insoluble noncationic antibacterial agent, andmixtures thereof.
 3. A process according to claim 2, wherein saidforming of said first low viscosity homogenous slurry comprises addingwith mixing at 100 to 400 rpms for 5 to 20 minutes said gelling agent tosaid nonaqueous solvent.
 4. A process according to claim 3, wherein saidforming of said second low viscosity fluid comprises adding with mixingat 100 to 400 rpms for 5 to 30 minutes at least one polishing agent andat least one said other additive ingredient.
 5. A process according toclaim 4, wherein said forming of said homogenous low viscosity slurrycomprises mixing said first low viscosity slurry with said second lowviscosity slurry in an in-line static mixer.
 6. A process according toclaim 5, wherein said transforming of said low viscosity mixture into anon Newtonian mixture comprises holding said low viscosity mixture atatmospheric condition in a tank without mixing at a temperature of 90°F. to 120° F. for 15 to 30 minutes thereby permitting said gelling agentto hydrate and swell.
 7. A process according to claim 6, wherein saiddeaerating of and polishing of said non Newtonian mixture comprisescontinuously passing said non Newtonian mixture through a Versator toform said paste or cream like material.
 8. A process according to claim7, further including passing said paste or cream like material through ascreen filter.
 9. A process according to claim 1, wherein said paste orcream like material comprises approximately by weight:(a) 1.0 to 40% ofat least one said non aqueous solvent; (b) 0.05 to 5.0% of at least onesaid bodying or gelling agent; (c) 0.5 to 50% of at least one polishingagent; (d) 0 to 0.75% of a water insoluble noncationic antibacterialagent; (e) 0 to 5% of an anticalculus agent; (f) 0.05 to 3% of at leastone surface active material; (g) 0.1 to 1.5% of a flavoring agent; (h) afluoride containing compound in a sufficient amount to provide 0 to5,000 ppms of fluoride ions; (i) 0 to 3% of a polymeric material; (j) 0to 5% of an alkali metal phosphate; (k) 0 to 5% of an alkali metalphosphate; and (l) balance being water.
 10. A process according to claim9, wherein such gelling agent is a selected from the group consistingessentially of natural gums, synthetic gums, sodium carboxymethylcellulose, hydroxyethyl carboxymethyl cellulose and clays and mixturesthereof.
 11. A process according to claim 10, wherein said polishingagent material is selected from the group consisting essentially ofcalcium carbonate, crystalline silica, colloidal silica, complex aluminosilicate, aluminum hydroxide, aluminum silicate, dicalcium phosphatedihydrate and silica xerogels and mixtures thereof.
 12. A processaccording to claim 12, wherein said surface active material is a sulfatecontaining compound.
 13. A process according to claim 12, wherein saidfluoride containing compound are inorganic fluoride salts.
 14. A processaccording to claim 13, wherein said polymeric material is a copolymer ofmethyl vinyl ether and maleic anhydride.
 15. A process according toclaim 14, wherein said alkali metal phosphate is an alkali metalpyrophosphate.
 16. A process for preparing a non Newtonian paste orcream like material which comprises the step of transforming said lowviscosity mixture in a maturing tank under non vacuum conditions atatmospheric pressure and without mixing or stirring at a temperature ofabout 100° F. to about 120° F. for about 15 to about 60 minutes into ahigh viscosity non Newtonian mixture; said low viscosity mixturecomprising water, a non aqueous solvent and a bodying agent or a gellingagent.